Muffle-furnace



(No Model.)

C. H. LAND.

MUPPLB PURNAGB. No. 446,947. Patented Feb. 24, 1891,..

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fm mffmp( wei-ew 3 www UNITED STATES PATENT OFFICE.

CHARLES I'I. LAND, OF DETROIT, MICHIGAN.

lVlUFFLE-FURNACE.

SPECIFICATION forming part of LettersPatent No. 446,947', dated February 24, 1891.

Application tiled August 3l, 1889. Serial No. 322,542. (No model.)

' the following to be a full, clear, and exact description of the same, such as will -enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specication.

My invent-ion relates to a new and useful apparatus for controlling chemical effects on various substances while under the influence of various degrees of heat, so as to secure at the will of the operator definite chemical effects desired free from contamination from foreign matter. f

I carry out my invention as more particu larly hereinafter described and claimed, and

illustrated in the accompanying drawings, in

which- Figure l is a view in perspective illustrating features of myinvention. Fig. 2 is avertical longitudinal section. Fig. 3 is a vertical cross-section showing the muti-les inclosed in a furnace, and Fig. 4 is a vertical section illustrating a modification of my invention.

This invention is more particularly designed as an improvement on features embodied in United States Letters Patent granted to me January 3, 1888, No. 376,003.

The apparatus employed in my present invention consists of a muffle, retort, crucible, oven, or other analogous device constituting aninner receptacle, the same being located within an outer receptacle and forming an intermediate space between said receptacles, which in turn are located within the combustion-chamber of afurnace, the construction and arrangement vbeing such that an independent air or gas space is interposed between the inner receptacle and the products of combustion in the combustion-chamber, through which space the atmosphere or any determined gas or gases or the lvapors of metals may be circulated to secure the desired action upon the substances placed within the inner receptacle and to protect said substances from injurious results while under the induence of heat in said combustionchamber.

Accordingly, A represents the outer munie, B the inner mufe, and C the intermediate space between the two receptacles. The front ofV said space may be closed in any desired manner, as by an asbestus wall or packing D, which for certain purposes may be perforated, as shown at d, to afford an outlet for the atmosphere, gas, or vapors caused to circulate about the inner receptacle through said space.

E represents` an inlet-conduit communieating with said space C, and through which any desired gas or gases or vapors or the atmosphere may be conducted into said space. Instead of perforating the wall D, as shown at d, said space may be provided with any desired outlet.

In some cases itwill be desirable to inject the gas, atmosphere, or vapor into the inner receptacle and to discharge it from the mouth thereof. Accordingly my inventionV contemplates perforating the interior muftle B at any desired point or points, as shown, for example, at l).

F represents the furnace, in the combustion-chamber of which the two receptacles are located. F is a burnerled therethrough. This furnace may be of any well-known or improved construction; but as shown in the drawings it is provided with a heat-retaining packing F2, over which is secured a metallic covering F3. The muffles may be provided with lugs a a. to keep them in place and to insure free circulation about the inner receptacle.

In Fig. et I have shown two crucibles HH', the one located within the other, forming an intermediate space h between them. The crucibles are supported in any desired furnace or heating apparatus I. The crucibles may or may not be provided with a hood h h2, respectively, the space 7L opening upward through and between the hoods, as shown. These hoods, if employed, may be removable to afford access to the interior of the inner Crucible. An inlet-pipe .I may lead through the case of the furnace into the space h and a tube K connect a pressure device K with said inlet-pipe for injecting the gas, atmos- IOO phere, or vapor into said space under pressure.

It will be evident that by locating the substance to be acted upon within the interior inutile said substance, when subjected to heat within the combustion-chamber of the furnace, may readily be separated from the deleterious products of combustion in said chamu ber and from other injurious influences by enveloping said substance within an air, gas, or vapor space wholly independent ot' and separate from vthe products of combustion in the combastion-chamber. It is equallyobvious that the gases, atmosphere, or vapors introduced into said space may be wholly distinct from said products of combustion in the comb ustion-chamber, and also from any gases otherwise present or generated in the inner receptacle. This feature of surrounding the work in the interior mutiie within such an air, gas, or vapor space, separating it from l the products of combustion in the combus; tion-chaniber, and of introducing` into said space any desired gas, atmosphere, or vapor enables lne to etiectually regulate and conf trol the chemical effects produced within the f interior niuiile. facture ot' porcelain wares, as'artilicial teeth, for instance. ln such manufacture by means of my invention embodied inthe Letters Patent above referred to, when air was injected directly into the mufile containing the work, in order to force out deleterious gases or to Take,forexample,the manui introduce a desired gas directly to the work within the muiiie, it was found thatthe torce of the current injected in a large volume was apt to carry small particles of matter with it in a measure injurious tothe work. lly injecting the current, however, between two muflies into an intermediate space in the manner herein described any such injury I entirely overcome and much more uniform l and perfect elfccts are secured. l have demonstrated, also, that free carbon, either conveyed through the monoxide of carbon or an excess of hydrocarbon, has a tendency at high temperatures within the combustion-chamber 1 of a muiiie furnace to give up its carbon and unite with the oxides ot' the work within the mutiie and with the oxides of the muftle itself unless guarded against, tending to deoxidize the workef certain description such as porcelain, for example-as well as injuring the muiiie. To guard against such a. liability, my improved device is found peculiarly well adapted, as thereby a current of air may be circulated about the inner muflle to protect it and the work from the liability of injury above described. Air or any other suitable gases or vapors may be so introduced into the intermediate space to drive olf anyinjurious gases and prevent their ventrance into the mul'tle; or a suitable gas can be introduced into said space to unite with an injurious gas and change it to one of a harmless character at the proper temperature. Thus monoxide of carbon may be changed to dioxide of carbon by the introduction of oxygen into the said space at a suitable temperature.

For another example illustrating the application of my improved device attention is called thereto as an adequate prevention of the oxidation of metals within the muilie when subjected to high degrees of heat in the combustionchamber, as inthe tempering of steel. ly this device l am able to maintain an atmosphere of nitrogen or hydrogen, for instance, about vand in the inner receptacle, by means of which the steel may be brought to the desired temperature without oxidation, the steel being immersed in the nitrogen or hydrogen, oxygen being excluded thereby from the inner receptacle. The same is true where other gases or vapors are similarly injected for analogous purposes.

VWhere oxygen is desired, it maybe uniformly and rapidly injected into the interior muitle to oxidize a given substance placed therein, as in assay work, where this method is of greatest practical utility and value.

\\'hat I claim isl. In an apparatus for controlling chemical effects, the combination, with the furnace, of an outer receptacle located therein and spa-ced therefrom, an innerreceptaclc located within the outer receptacle and spaced therefrom to form an air or gas space, said air or gas space havingan inlet and outlet, means for conveying to said space air, gas, or vapor, and a burner or heating means communicating with the space formed between the furnace and outer receptacle.

2. 1n an apparatus for controllingchemical effects, the combination,with the furnace, of an outer receptacle located therein and spaced therefrom, an inner receptacle located within the outer receptacle and spaced therefrom to form an air or gas space communicating with the inner receptacle and provided withan inlet, means for conveying to said space air, gas, or vapor, anda burneror heating means communicating with the space formed between the furnace and the outer receptacle.

In testimony whereof I sign this specification in the presence of two witnesses.

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